We use your utility usage history, seasonal patterns, and information about your home to estimate how much gas is used by each of your appliances.
Most homes have just one gas meter and don't track how much is used by individual appliances. Often, though, as long as we know how much gas you've used in each month for a full year, we can make some educated guesses to help you understand what's using the most gas -- and producing the most carbon pollution -- in your home
First, we estimate gas usage from cooking and clothes drying. These tend to be a smaller portion of home gas usage (under 20%, and often under 10%) and are more consistent throughout the year. Clothes drying depends on how many occupants you have in the home and how much laundry you do, and cooking depends on how much you tend to cook at home.
Next, we figure out gas for water heating. Here, we look at the summer months to determine a baseline. In most climates, after accounting for cooking and clothes drying, the remaining gas usage will be from water heat because we generally don't run our furnaces for space heating in the summer. We use the summer average to project water heating use through all months of the year, accounting for a little more energy during colder months, when incoming water temperatures are colder and people might take longer showers.
Finally, we assume that any remaining gas usage is for space heating.
The following chart shows a home with a clear seasonal curve. Clothes drying and cooking are fixed, and the water heat usage is estimated using the low summer months of July, August, and September, projecting out to the rest of the year. Space heating is the remainder of gas use in the other months.
This method works well for most homes that use gas for the standard functions of space heating, water heating, cooking, and / or clothes drying. It can get more complicated in homes with gas pool or spa heaters, outdoor gas heaters or fire pits, significant summer heating needs, or sporadic occupancy. Still, even rough estimates can help homeowners understand and prioritize electrification projects based on the amount of gas consumed and the potential utility bill savings when upgrading to efficient, electric appliances.